CN109587610B

CN109587610B - Sound converter

Info

Publication number: CN109587610B
Application number: CN201810437545.7A
Authority: CN
Inventors: 金千明; 郑性哲; 南瑟基; 河敬辅
Original assignee: EM Tech Co Ltd
Current assignee: EM Tech Co Ltd
Priority date: 2017-09-29
Filing date: 2018-05-09
Publication date: 2020-12-15
Anticipated expiration: 2038-05-09
Also published as: CN109587610A; US20190104369A1; US10728672B2

Abstract

The present invention relates to a sound converter, and more particularly to a sound converter including a suspension for connecting a lower end portion or a lower end portion side surface of a voice coil to a frame to suppress split vibration. The sound converter includes: a frame; a bottom plate comprising an outer bottom plate and an inner bottom plate; a top plate comprising an outer top plate and an inner top plate; a central magnet mounted between the inner top plate and the inner bottom plate; first to fourth sub-magnets installed between the outer top plate and the outer bottom plate and spaced apart from the central magnet by a magnetic gap; a first suspension device comprising a central dome and an edge dome mounted at a topmost portion of the frame; a second suspension device including an FPCB and attached to the bottom surface of the diaphragm; a voice coil having a lower end positioned in the magnetic gap and having an upper end attached to the bottom surface of the second suspension; and a third suspension device including first to fourth dampers connecting the lower end portions of the voice coils to the frame through respective spaces between the sub-magnets.

Description

Sound converter

Technical Field

The present invention relates to a sound converter, and more particularly, to a sound converter including a suspension for connecting a lower end portion or a lower end portion side surface of a voice coil to a frame to suppress split vibration (split vibration).

Background

Conventional sound converters (e.g., micro-speakers, etc.) do not use a broadband sound source due to limitations of communication technology. However, as information communication technology has been developed, a reproduction bandwidth of a sound source to be reproduced in a sound converter has been widened, and the structure of the conventional sound converter has a limitation in characteristics and reliability as required power increases.

In order to solve these problems, the present applicant filed and registered korean patent No.10-1200435 (hereinafter, referred to as "conventional patent") entitled "High power microspaker" including: a frame; a protector; a yoke assembly coupled to the frame and having a magnet; a diaphragm disposed in the frame to generate vibration; a voice coil coupled to the diaphragm to vibrate the diaphragm; a terminal disposed at one side of the frame to provide an electrical connection between the external terminal and a lead of the voice coil; and a damper formed of an FPCB (flexible printed circuit board), the damper having an inner portion to which a center diaphragm, a side diaphragm, and a voice coil are attached, a side diaphragm attached to the outer portion and the outer portion in contact with the frame and the protector, a support portion for connecting the voice coil, the outer portion, and the inner portion, and the support portion including a platform portion to which lead-in wires of the coil are soldered or welded, and a connection portion extending to an outside of the outer portion and providing an electrical connection between the outer portion and a terminal disposed at the frame.

This conventional patent of the present applicant is limited in suppressing the split vibration because the vibration system includes a diaphragm, a damper formed of an FPCB, and a voice coil, wherein there is a small distance between the diaphragm and the damper and a relatively large distance from a lower end portion of the voice coil, wherein the movement is generated by a magnetic force.

In addition, the conventional patent of the present applicant has a risk of thermal deformation because fresh air does not smoothly flow into the diaphragm.

Disclosure of Invention

An object of the present invention is to provide a sound converter including a suspension for connecting a lower end portion or a lower end portion side surface of a voice coil to a frame to suppress split vibration, and which contributes to an internal flow of air to lower the temperature of a diaphragm.

The sound converter according to the present invention includes: a frame; a bottom plate including an outer bottom plate and an inner bottom plate; a top plate including an outer top plate and an inner top plate; a central magnet mounted between the inner top plate and the inner bottom plate; first, second, third and fourth sub-magnets mounted between the outer top and bottom plates and spaced apart from the central magnet by a distance (magnetic gap); a first suspension device comprising a central dome and an edge dome mounted at a topmost portion of the frame; a second suspension device including an FPCB and attached to the bottom surface of the diaphragm; a voice coil having a lower end positioned in a magnetic gap between the central magnet and the first, second, third and fourth sub-magnets and an upper end attached to a bottom surface of the second suspension; and a third suspension device including a first damper, a second damper, a third damper, and a fourth damper for connecting the lower end portion of the voice coil to the frame through respective spaces between the first and second sub-magnets and the third and fourth sub-magnets.

According to the present invention, a vibration system, which includes a first suspension, a voice coil, a second suspension attached to an upper end portion of the voice coil, and a third suspension attached to a lower end portion or a lower end portion side surface of the voice coil, suppresses split vibration.

In addition, according to the present invention, a plurality of opening portions are formed at the corners of the outer top plate to facilitate the flow of air in the sound converter, which reduces internal heat, particularly in high-power applications, thereby suppressing deformation of the diaphragm and improving THD (total harmonic distortion).

Further, according to the present invention, in the structure of the rectangular sound converter, it is possible to compensate for the difference in rigidity of the diaphragm between the long side and the short side.

Drawings

Fig. 1 is an exploded perspective view of a sound converter according to the present invention.

Fig. 2 is a perspective view of a sound converter according to the present invention.

Fig. 3 is a sectional perspective view taken along line a-a' of fig. 2.

Fig. 4A and 4B are graphs showing the vertical vibration amplitude of the vibration system of the related art and the vertical vibration amplitude of the vibration system of the present invention.

Fig. 5A and 5B are graphs showing the THD of the prior art sound converter and the THD of the sound converter of the present invention.

Fig. 6A to 6C are graphs showing the relationship between the corner width a of the damper portion 71C and the width B of the long-axis straight-line portion or the short-axis straight-line portion of the dome 44C.

Fig. 7A and 7B are graphs showing the relationship between the corner width a of the damper portion 71C and the corner width C of the connecting portion between the long-axis straight-line portion and the short-axis straight-line portion of the dome 44C.

Detailed Description

Hereinafter, preferred embodiments of a sound converter according to the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is an exploded perspective view of a sound converter according to the present invention, fig. 2 is a perspective view of a sound converter according to the present invention, and fig. 3 is a sectional perspective view taken along line a-a' of fig. 2.

The sound converter includes: a frame 10; a base plate installed on a bottom surface of the frame 10 and including an outer base plate 22 and an inner base plate 23; a top plate including an outer top plate 24 and an inner top plate 26; a central magnet 32, the central magnet 32 being mounted between the inner top plate 26 and the inner bottom plate 23; first, second, third and

fourth sub-magnets

34a, 34b, 36a, 36b, respectively, mounted between the outer top and

bottom plates

24, 22 and spaced apart from the central magnet 32 by a distance (magnetic gap); a first suspension device 40, the first suspension device 40 including a central dome 42 and an edge dome 44 mounted at a topmost portion of the frame 10, the first suspension device 40 being configured to vibrate; a second suspension device 50, the second suspension device 50 including, for example, an FPCB or the like and being attached to the bottom surface of the diaphragm 40, the second suspension device 50 being configured to vibrate; a voice coil 60 having a lower end portion positioned in a magnetic gap between the central magnet 32 and the first, second, third, and

fourth sub-magnets

34a, 34b, 36a, 36b, and having an upper end portion attached to a bottom surface of the second suspension 50; and a third suspension device including first, second, third and

fourth dampers

70a, 70b, 70c and 70d for connecting the lower end portion of the voice coil 60 to the frame through respective spaces between the first and

second sub-magnets

34a and 34b and the third and

fourth sub-magnets

36a and 36b, the third suspension device being configured to vibrate. The sound converter according to the present invention comprises a vibration system comprising a voice coil 60, a first suspension 40, a second suspension 50 and a third suspension, wherein the first suspension 40 and the second suspension 50 are attached to an upper end of the voice coil 60. The sound converter according to the present invention includes a magnetic circuit including a top plate, a bottom plate, a magnet (central magnet 32), and first, second, third, and

fourth sub-magnets

34a, 34b, 36a, and 36b installed between the top plate and the bottom plate to define a magnetic gap.

More specifically, the frame 10 has a hollow rectangular structure. The combined first and

second suspension devices

40 and 50 are seated on the top surface of the frame 10, the outer top plate 24 is seated on the top surface of the four corners of the frame 10, and the first, second, third, and

fourth seats

10a, 10b, 10c, and 10d are provided on the inner or inner bottom surfaces of the four corners of the frame 10, wherein one end portions of the first, second, third, and

fourth dampers

70a, 70b, 70c, and 70d are attached to the first, second, third, and

fourth seats

10a, 10b, 10c, and 10 d. In addition, the frame 10 includes a first terminal 12a and a second terminal 12b, and the first terminal 12a and the second terminal 12b are used for receiving an electrical signal from a controller (not shown) of the electronic device (the controller is, for example, a microprocessor or the like).

The bottom plates include an outer bottom plate 22 and an inner bottom plate 23, the outer bottom plate 22 and the inner bottom plate 23 are formed in a single piece, with a groove 22a between the outer bottom plate 22 and the inner bottom plate 23. The groove 22a serves to prevent the voice coil 50 from striking the bottom plate when vibrating. First and

second sub-magnets

34a and 34b are respectively attached in a parallel manner to the long axis of outer bottom plate 22, and third and

fourth sub-magnets

36a and 36b are respectively attached in a parallel manner to the short axis of outer bottom plate 22.

The top plate includes an outer top plate 24 and an inner top plate 26, the outer top plate 24 and the inner top plate 26 being spaced apart from each other by at least one magnetic gap. The outer top plate 24 includes: a first long axis part 24a and a second long axis part 24b parallel to each other, the first sub magnet 34a being attached to a bottom surface of the first long axis part 24a, the second sub magnet 34b being attached to a bottom surface of the second long axis part 24 b; a first stub portion 24c and a second stub portion 24d parallel to each other, a third sub-magnet 36a attached to a bottom surface of the second stub portion 24d, and a fourth sub-magnet 36b attached to a bottom surface of the first stub portion 24 c; and a first connecting portion C1, a second connecting portion C2, a third connecting portion C3, and a fourth connecting portion C4 (i.e., respective corners of the outer top panel 24), the first connecting portion C1, the second connecting portion C2, the third connecting portion C3, and the fourth connecting portion C4 connecting the first long-axis portion 24a and the second long-axis portion 24b to the first short-axis portion 24C and the second short-axis portion 24d, respectively, a first opening portion H1 formed in the first connecting portion C1, a second opening portion H2 formed in the second connecting portion C2, a third opening portion H3 formed in the third connecting portion C3, and a fourth opening portion H4 formed in the fourth connecting portion C4. Even when an electric signal for high output is applied to the voice coil 60, the first opening portion H1, the second opening portion H2, the third opening portion H3, the fourth opening portion H4 serve to facilitate the flow of air between the inside of the second suspension 50 and the bottom of the second suspension 50 to reduce heat of the inside, which suppresses deformation of the diaphragm and improves THD. Further, a first groove 26a and a second groove 26b are formed on the long-axis side of the inner top plate 26 to prevent the second suspension device 50 from hitting the first protrusion 58a and the second protrusion 58b when vibrating.

The center magnet 32 is seated at the center of the outer top plate 24 and the outer bottom plate 23, and the first, second, third, and

fourth sub-magnets

34a, 34b, 36a, 36b are installed to be spaced apart from the outer side surface of the center magnet 32 by a magnetic gap. In addition, the first sub magnet 34a is spaced apart from the third and

fourth sub magnets

36a and 36b by a distance corresponding to the first and fourth connection portions C1 and C4 or the first sub magnet 34a is spaced apart from the third and

fourth sub magnets

36a and 36b by the first and fourth opening portions H1 and H4, and the second sub magnet 34b is spaced apart from the third and

fourth sub magnets

36a and 36b by a distance corresponding to the second and third portions C2 and C3 or the second sub magnet 34b is spaced apart from the third and

fourth sub magnets

36a and 36b by the second and third opening portions H2 and H3. In this embodiment, the first sub-magnet 34a, the second sub-magnet 34b, the third sub-magnet 36a, and the fourth sub-magnet 36b are provided so as to correspond to the four side portions of the center magnet 32. However, it is also possible that only the first sub-magnet 34a and the second sub-magnet 34b are provided so as to correspond to the major axis side of the center magnet 32, or only the third sub-magnet 36a and the fourth sub-magnet 36b are provided so as to correspond to the minor axis side of the center magnet 32.

The first suspension device 40 includes a center dome 42 and an edge dome 44, the edge dome 44 including a first seat portion 44a, a second seat portion 44b, and a dome 44c, wherein an outer peripheral portion of the center dome 42 is seated on the first seat portion 44a, the second seat portion 44b is seated on the frame 10, and the dome 44c is interposed between the first seat portion 44a and the second seat portion 44 b.

The second suspension device 50 includes: an inner peripheral portion 52, the inner peripheral portion 52 being attached to the bottom surface of the first seat 44 a; an outer peripheral portion 54, the outer peripheral portion 54 being attached to the bottom surface of the second seat 44 b; first, second, third, and

fourth bridge portions

56a, 56b, 56c, and 56d for connecting the inner peripheral portion 52 to the outer peripheral portion 54; first and second protruding

portions

58a and 58b, the first and second protruding

portions

58a and 58b protruding in the center direction from the long axis side of the inner peripheral portion 52; and third and fourth protruding

portions

58c and 58d, the third and fourth protruding

portions

58c and 58d protruding in the center direction from the major axis side of the outer peripheral portion 54 between the outer peripheral portion 54 and the inner peripheral portion 52. The inner peripheral portion 52 includes a first conductive portion and a second conductive portion (not shown) electrically insulated from each other, the first conductive portion being electrically connected to the first lead wire 62a of the voice coil 60 through the first protrusion 58a having conductivity, and the second conductive portion being electrically connected to the second lead wire 62b of the voice coil 60 through the second protrusion 58b having conductivity. The outer peripheral portion 54 includes a third conductive portion and a fourth conductive portion (not shown) electrically insulated from each other, the third conductive portion being electrically connected to the first terminal 12a in electrical contact with the third projection 58c having conductivity, and the fourth conductive portion being electrically connected to the second terminal 12b in electrical contact with the fourth projection 58d having conductivity. The first conductive portion and the third conductive portion are electrically connected by one of the first bridge portion 56a and the second bridge portion 56b having conductivity, and the second conductive portion and the fourth conductive portion are electrically connected by one of the third bridge portion 56c and the fourth bridge portion 56d having conductivity. Further, the first, second, third, and

fourth bridge portions

56a, 56b, 56c, and 56d are used to connect the inside of the short axis of the outer peripheral portion 54 to the outside of the long axis of the inner peripheral portion 52, or to connect the inside of the long axis of the outer peripheral portion 54 to the outside of the short axis of the inner peripheral portion 52, so that the first, second, third, and

fourth bridge portions

56a, 56b, 56c, and 56d are arranged equidistantly in the long and short axis directions, in order to prevent the inner peripheral portion 52 from rotating or twisting in the long and short axis directions even when a large power signal is applied to the voice coil 60, thereby preventing split vibration at the time of vertical vibration of the voice coil 60.

The voice coil 60 may be wound around a voice coil bobbin, an upper end portion of which is attached to the bottom surface of the inner peripheral portion 52 of the second suspension 50, and a lower end portion of which is positioned in the magnetic gap.

The third suspension device includes a first damper 70a, a second damper 70b, a third damper 70c, and a fourth damper 70d, each of the first damper 70a, the second damper 70b, the third damper 70c, and the fourth damper 70d includes a first attachment portion 71a, a second attachment portion 71b, and a damper portion 71c, the first attachment portion 71a is attached to a bottom surface of each of the first seat 10a, the second seat 10b, the third seat 10c, and the fourth seat 10d, the second attachment portion 71b is attached to a lower end portion or a lower end side surface of the voice coil 60, and the damper portion 71c is used to connect the first attachment portion 71a to the second attachment portion 71 b. The first damper 70a, the second damper 70b, the third damper 70c, and the fourth damper 70d are positioned in or below a space in which the first opening H1, the second opening portion H2, the third opening portion H3, and the fourth opening portion H4 are formed. The lower end portion of the voice coil 60 is connected to the frame 10 below the first opening H1, the second opening portion H2, the third opening portion H3, and the fourth opening portion H4, which balances the vertical vibration amplitude of the vibration system to prevent split vibration, and which suppresses an increase in harmonic components, thereby reducing Total Harmonic Distortion (THD).

Further, in this embodiment, the damper portion 71c has a dome-like structure facing the downward direction of the frame 10, but the damper portion 71c may extend almost horizontally between the lower end portion of the voice coil 60 and the frame 10 and have a plurality of curved portions (waves), or the damper portion 71c may extend in a convex manner in the downward direction of the frame 10 and have a plurality of curved portions (waves).

Fig. 4A and 4B are graphs showing the vertical vibration amplitude of the vibration system of the related art and the vertical vibration amplitude of the vibration system of the present invention. The prior art vertical vibration amplitude graph in fig. 4A shows an amplitude up to about 0.35mm according to the frequency of the applied electrical signal at the time of vertical vibration, while the vertical vibration amplitude graph of the present invention in fig. 4B shows an amplitude up to about 0.29mm according to the frequency of the applied electrical signal at the time of vertical vibration. It can be seen in fig. 4A and 4B that the provision of the third suspension arrangement balances the vertical vibration amplitude of the vibration system, thereby suppressing the splitting vibration.

Fig. 5A and 5B are graphs showing the THD of the prior art sound converter and the THD of the sound converter of the present invention. The THD graph of the prior art sound converter in fig. 5A shows that the THD is up to about 60% at a low frequency band according to the frequency of the electric signal applied at the time of vertical vibration, while the THD graph of the sound converter of the present invention in fig. 5B shows that the THD is up to about 25% at a low frequency band according to the frequency of the electric signal applied at the time of vertical vibration. As can be seen in fig. 5A and 5B, the provision of the third suspension suppresses the increase of the harmonic component, thereby significantly reducing THD.

In fig. 3, the corner width a of the damper portion 71C provided in the first, second, third, and

fourth dampers

70a, 70B, 70C, and 70d, the width B of the long-axis or short-axis linear portion of the dome 44C, and the corner width C of the connecting portion between the long-axis linear portion and the short-axis linear portion of the dome 44C have an influence on the vibration control of the vibration system. The above width preferably satisfies one of the following expressions 1 and 2, so that the vertical vibration amplitude of the vibration system is uniformly controlled.

Expression 1

A≥B

Expression 2

A≤C

First, with regard to expression 1, fig. 6A to 6C are graphs showing the relationship between the corner width a of the damper portion 71C and the width B of the long-axis straight-line portion or the short-axis straight-line portion of the dome 44C.

FIG. 6A shows Sound Pressure Level (SPL), where the solid curve is obtained with A ≧ B and the dashed curve is obtained with A < B. As shown in fig. 6A, it can be seen that spl (db) of the solid line curve satisfying expression 1 is higher than spl (db) of the dotted line curve at most frequency bands.

FIG. 6B shows Total Harmonic Distortion (THD), where the dashed curve is obtained for A ≧ B and the solid curve is obtained for A < B. As shown in fig. 6B, it can be seen that the distortion rate (%) of the dotted-line curve satisfying expression 1 is much lower than that (%) of the solid-line curve in the case of less than 1kHz and is similar to that (%) of the solid-line curve in the case of more than 1 kHz.

FIG. 6C shows the amplitude of the vibrating portion, in which the solid-line curve is obtained in the case of A ≧ B and the black-dashed-line curve is obtained in the case of A < B. As shown in fig. 6C, it can be seen that the amplitudes of the solid-line curves satisfying expression 1 are symmetrical in the upward and downward directions (i.e., the amplitudes are uniform in the vertical direction), while the amplitudes of the black-dashed curves are non-uniform at some frequency bands in the vertical direction.

Based on the description of fig. 6A to 6C, it is preferable that the corner width a of the damper portion 71C and the width B of the major axis side portion or the minor axis side portion of the dome 44C satisfy expression 1.

Next, with regard to expression 2, fig. 7A and 7B are graphs showing the relationship between the corner width a of the damper portion 71C and the corner width C of the connecting portion between the long-axis linear portion and the short-axis linear portion of the dome 44C.

Fig. 7A shows a graph obtained in the case where the corner width a is larger than the corner width C. It can be seen that the curves of the upward vibration (dotted lines) and the downward vibration (solid lines) are not uniform, which results in the splitting vibration.

Fig. 7B shows a graph obtained in the case where the corner width a is equal to or smaller than the corner width C. It can be seen that the curve of the upward vibration (dotted line) and the curve of the downward vibration (solid line) are uniform, which prevents the split vibration.

While the invention has been illustrated and described in connection with the drawings and the preferred embodiments, the invention is not limited thereto and is defined by the appended claims. Accordingly, it will be understood by those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. An acoustic transducer comprising:

a rectangular frame;

a first suspension device seated on an upper side of the frame to vibrate;

a second suspension attached to a bottom surface of the first suspension and electrically connected to a voice coil to vibrate;

a magnetic circuit comprising a central magnet, a plurality of secondary magnets spaced a distance from the central magnet to define a magnetic gap, a plurality of top plates positioned above the central magnet and each of the plurality of secondary magnets, and a bottom plate positioned below the central magnet and each of the plurality of secondary magnets;

a voice coil attached to a bottom surface of the second suspension; and

a third suspension device connecting a lower end portion or a lower end portion side surface of the voice coil to the frame to vibrate,

wherein the third suspension device is positioned to pass through a space defined by the plurality of secondary magnets spaced apart from each other,

wherein the third suspension device includes a plurality of dampers including a first attachment portion attached to a bottom surface of a seat portion of the frame, a second attachment portion attached to the lower end portion or the lower end side surface of the voice coil, and a damper portion for connecting the first attachment portion to the second attachment portion,

the first suspension device includes an edge dome including a first seat on which an outer peripheral portion of the center dome is seated, a second seat on which the second seat is seated on the frame, and a dome interposed between the first seat and the second seat,

wherein a corner width of the damper portion is greater than a width of a straight portion of the dome of the edge dome.

2. An acoustic transducer comprising:

a rectangular frame;

a first suspension device seated on an upper side of the frame to vibrate;

a voice coil attached to a bottom surface of the second suspension; and

wherein a corner width of the damper portion is smaller than a corner width of a connection portion between straight portions of the domes of the edge domes.

3. The sound converter according to claim 1 or 2, wherein the damper portion has a dome-like structure facing a downward direction of the frame, a structure extending horizontally between the voice coil and the frame with a plurality of bends, or a structure extending convexly in the downward direction of the frame between the voice coil and the frame with a plurality of bends.

4. The sound converter according to claim 1 or 2, wherein the plurality of top plates include an inner top plate attached to an upper side of the central magnet and an outer top plate spaced apart from the inner top plate by at least the magnetic gap, the plurality of sub-magnets are attached to the outer top plate, and opening portions are formed in corners of the outer top plate.

5. The sound converter according to claim 4, wherein the third suspension device is positioned in or below a space in which the opening portion is formed.

6. The sound converter according to claim 1 or 2, wherein the second suspension device includes an inner peripheral portion attached to a bottom surface of the first seat, an outer peripheral portion attached to a bottom surface of the second seat, and a plurality of bridges for connecting the inner peripheral portion to the outer peripheral portion of the second suspension device, each of the bridges connecting a short-axis inside of the outer peripheral portion of the second suspension device to a long-axis outside of the inner peripheral portion.

7. The sound converter of claim 1 or 2, wherein the base plate comprises an inner base plate and an outer base plate, wherein the central magnet is mounted on the inner base plate and the plurality of sub-magnets are mounted on the outer base plate, the inner and outer base plates being formed as a single piece in which there is a groove between the inner and outer base plates.